Of same place



(No Model.) 2 SheeQs-Sheet 1.

W. W. DEAN ELECTRIC SWITGHING APPARATUS.

AN DREW BLRAHAM. FHDYo-LrmawAsHl NGION n.0

(No Model.) 2 Sheets-'Sheet 2.

W. W. DEAN.

f ELECTRIC SWITGHING APPARATUS. No. 559,792. Patented May 12, 1896.

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VILLlAM lV. DEAN, OF ST. LOUIS, MISSOURI, ASSIGNOR TO THE BELL TELE- PHONE COMPANY OF MISSOURI, OF SAME PLACE.

ELECTRIC SWITCHING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 559,792, dated May 12, 1896.

Application filed January Z4, 1896. Serial No. 576,649. (No model.)

To all whom it may con/cern.- necting-plug inserted therein. Fig. Gis a plan Be it known that l, WILLIAM XV. DEAN, a view of the connecting-plug. Fig. 7 is a seccitizen of the United States, residing at St. tional plan view of the connecting-plug. Fig. Louis, in the State of Missouri, have invented Y 8 is an end elevation of the connecting-plug, 5 5

5 a certain new and useful Improvement in looking toward the tip. Fig. 9 is a sectional Electric Switching Apparatus, (Oase No. (5,) view thereof on line 9 9 of Fig. 5. Fig. l0 is a of which the following is a full, clear, concise, diagram illustrating two telephone-lines conand exact description, reference being had to nected together through the medium of my the accompanying' drawings, forming a part improved switching apparatus. 6o

1o of this specification. Like letters and numerals refer to like parts Myinvention relates to switching apparatus throughout the several iigures. of the kind usually employed at switchboards I will first describe in detail the mechanof telephone-exchanges in connecting and disical construction of the terminal plugs and the y connecting the telephone-lines. spring-jacks in which the same are adapted to 65 15 Speaking generally, myinvention comprises be inserted. The central or core portion a is aspring-jack switch consisting of line-springs, provided with a binding-screw d', adapted to in thisinstance fourin number,betweenwhich secure one of the strands of the cord-circuit are placed contact postsor anvils; also a plug in electrical engagement therewith. Coaxiadapted to be inserted through a metallic ally about this core portion a are arranged the 7o zo thimble placed in front of the free or movable insulating-sleeve b, metallic sleeve c, insuends of the springs of the spring-jack, the lating-sleeve d, and metallic sleeve e, through plug being constructed when inserted to all of which is passed an insulating-pin j", spread or wedge the springs apart and sepaadapted to secure these portions of the plug rate them from their normal contacts with the in fixed relation with each other. The metal- 7 5 2 5 intervening posts or anvils and form new conlic sleeve c is provided with an offset or shoultacts between said springs and the contacts der c to secure a uniform diameter of the of the plug. The plug is provided with three shank. Insulating-sleeves l) and CZ are procontact portions, to each of which a separate vided with like offsets to follow the contour conductor of the cord-circuit is connected. of the metallic sleeve c upon its inner and 8o 3o Two of these contact terminals constitute outer surfaces.

outer portions of the tubular shank of the The metallic sleeve c is provided with a plug, while the other contact consists of a pin binding-screw c2, adapted to electrically unite placed centrally in the tubular shank, as will asecond cord-strand therewith. The metallic be hereinafter more particularly described. sleeve e is adapted to be electrically united S5 3 5 My switching apparatus may be adapted for with a third cord-strand. That portion of the usein various systems of telephone-exchange. metallic sleeve e which is handled by the op- I have, however, found it of particular aderator is provided with an insulating-jacket vantage on those systems in which local transe', which is made of a length sufficient to permitter-circuits of a large number of submit of the insertion of the plug to a proper 9o 4o scriber-stations are adapted to be supplied extent within the spring-jack switch. Porwith current from the central station. Such tions of the metallic sleeves c and e and the a system is shown in my Patent No. 546,731, insulating-sleeve d are removed, as shown granted September 2i, 1895. I will accordmost clearly in Figs. 5 and 7, to provide sufingly describe my invention as applied to ficient space to accommodate the cord-strands 95 45 such a telephone system. connected to the portions a and c.

In the drawings, which are illustrative of Referring to Fig. l0, the telephone-lines eX- my invention, Figure l is a plan view of my tend inrliinbs g g from the substations A and spring-jack. Fig. 2 is a side view thereof. B to the central station, limbs g g' terminat- Fig. 3 is a bottom view thereof. Fig. 4 is a ing in line-springs g2 g3, normally resting upon roo 5o front elevation of the spring-jack- Fig. 5 is contacts g* g5, which are both connected a plan view of my spring-jack with my conthrough individual indicators 71j 7L, preferably incandescent lamps, and the battery Z to ground, while limbs g g terminate in linesprings gG Q7, normally resting upon contacts g8, likewise connected with indicators 7L Z1, battery Z, and ground.

The sleeve c engages with the line-springs g2 and gS when the plug is inserted and removes the same from their respective contacts g4 and g5, thereby breaking the connection that previously existed through the medium of said contacts between said linesprings and the individual indicator ZL, the individual indicator being thereby .removed from circuit with the subscribers line. The core a of the plug is adapted to separate the line-springs g Q7 from their Contact g8, sufficient space being provided between said core and the insulating-sleeve b, interposed between the same and sleeve c, to permit of sufficient range of movement of the springs g Q7. The connection of the springs g Q7 with the indicator Zzy is also broken by their removal from vthe contact g8. The springjack is preferably constructed as shown in Figs. 1, 2, 3, 4, and 5. The various springs and contacts are preferably mounted upon a strip of insulating material e', upon which strip is provided a shoulder e" to secure the fixed ends of the springs, a clamping-plate 'Z2 being secured upon said shoulder above said springs to prevent the vertical displacement thereof. An additional shoulder or separate strip 3 is provided, in which are placed the thimbles Za, the axes thereof being preferably in line with the central contacts g8. The contacts g4 g g8 are extended through the insulating-strip 'L' and are riveted to metallic strips Z4 Z, which are extended to the rear of the insulating-strip e'. The metallic thimble 7s is riveted to the metallic strip t7, which likewise extends to the rear of the insulatingstrip Subscriber A, desiring conversation with subscriber B, removes his receiving-telephone from its hook, thereby establishing circuit from ground m in parallel over the limbs g g', line-springs g2 g3, and contacts g4 g5, through the lamp 71, and battery Z to ground, and also line-sprin gs 9G gl, contact g8, lamp Zt to ground. The operator, upon noticing that the lamp ZL burns, inserts the answering-plug l into the spring-jack corresponding with the line 0f subscriber A, ascertains the connection desired by bringing her telephone set into circuit with the subscribers line, and completes said connection by inserting the mate 2 of said plug into the spring-jack switch of the called-for subscriber. Upon the plug being thus inserted the indicating-lamp 7L is cut out of circuit with the subscribers line; but at the same time it is included in a normallyopen local grounded circuit which may be traced from the battery Z and its ground through the lamp 7L, strip e7, thimble 7c, conductor n, armaturen', and the grounded con tact n2, the circuit through the lamp being open at this contact during the time that the subscribers telephone is removed from its hook. During the time that the subseribers telephone is removed from the hook circuit is maintained from the ground at the subscribers station in parallel over the lines g g', line-springs g gT and core a, and line-springs g2 g3 and sleeve c, through the cord-strands connecting said core CL and sleeve c with the coil o of the repeating-coil o, thence through the connection p', relay p, battery Z to ground, whereby the armature n' is removed from its contact n2. Zhen the subscriber replaces the telephone upon its hook, relay p is (leenergized, the local grounded circuit through the indicator 7L being thereby closed, indicating to the operator that conversation has been finished, whereupon the operator withdraws the terminal plugs of the cord-circuit from the spring-jacks of the connected subscribers.

It should be observed that the resistance of the bells at the subscribers stations being high the current from battery Z, derived through the lamps ZL 7L, will not be sufficient to light them during thc time the telephones at said stations are hung up.

Vhile I have shown my improved forni of switching apparatus as being applied to a particular telephone-exchange system, it is obvious that it may be applied to other systems. I do not desire to limit myself to the precise construction shown; but,

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination with an electric connecting-plug provided with a core of conducting material and a sleeve surrounding the same to form an annular space about said core, of a spring-jack switch provided with four springs having their free ends in the same plane, said plug being adapted to be inserted in said spring-jack, the core .of said plug being adapted to wedge apart the two inner springs of the spring-jack switch and form contact therewith, and the sleeve of the said plug being adapted to wedge apart the outer of said springs and form contact therewith, substantially as and for the purpose specified.

2. In a switching apparatus, the combination of suitable contact-springs with a plug provided with a core adapted to engage with and move one or more of said springs, and a sleeve adapted to engage with and move one or more of said springs, a space intervening between said core and sleeve in which the spring or springs engaged by said core enter; substantially as described. Y

3. In a telephone-switchboard, the combination with a connecting-plug provided in the end with a pin or core forming one terminal or contact of the plug, an annular space being provided in the end of the plug surrounding said pin or core, of aspring-jack switch carrying a pair of line-springs between the ends of which said pin or core is adapted to be wedged when the plug is inserted in the IOO IIO

spring-jack switch to form electrical connection between said line-springs and said pin or core, the ends of the line-springs entering the annular space surrounding the pin or core; substantially as described.

4. In a telephone-switchboard, the combination with a connecting-plug provided with a tubular sleeve upon the end forming one of the plug-contacts, and with a centrallylocated pin or core situated within said tubular sleeve and forminganother ofthe plugcontacts, of a spring-jack switch comprising a pair of line-springs between the ends of which said tubular sleeve is adapted to be wedged when the plug is inserted in the spring-jack to complete electrical connection between said tubular sleeve and the said linesprings, and a pair of line-springs between the ends of which said pin orcore is adapted to be wedged when the plug is inserted to complete electrical connection between the said line-springs and said pin or core; substantially as described.

5. ln a telephone-switchboard, the combination with a connecting-plug provided upon the end with a tubular sleeve forming one of the plug-contacts and with a second sleeve situated to the rear of said tubular sleeve, insulated therefrom and forming a second plug-contact, said plug` being also provided with a centrally-located pin or core situated within said tubular sleeve, said core forming a third plug-contact, of a spring-jack switch comprising a pair of line-springs, each normally resting against a contact point or anvil7 the tubular sleeve carried upon the plug being adapted to be wedged between the ends of said -spring when the plug is inserted in the spring-jack to move said springs out of contact with their respective anvils and to complete electrical connection between the line-springs and said tubular sleeve, a pair of line-springs each normally resting against a contact point or anvil, between the ends of which springs the centrally-located pin or core is adapted to be wedged when the plug is inserted to move said line-springs out of contact with their respective anvils, and to complete electrical connection between said line-springs and said pin or core, and a ring or thimble, situated in front of said linesprings with which thimble the sleeve upon the plug situated to the rear of said tubular sleeve is adapted to make electrical Contact when the plug is inserted; substantially as described.

In witness whereof I hereunto subscribe my name this 20th day of January, A. D. 1896.

WM. YV. DEAN. lVitnesses:

W. L. FARRELL, ALBERT PIETooH. 

